<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>getSnapshotBeforeUpdate的使用场景</title>
  </head>

  <body>
    <div id="test"></div>

    <script type="text/javascript" src="../js/17.0.1/react.development.js"></script>
    <script
      type="text/javascript"
      src="../js/17.0.1/react-dom.development.js"
    ></script>
    <script type="text/javascript" src="../js/17.0.1/babel.min.js"></script>

    <script type="text/babel">

      class Time extends React.Component {

        state = {date: new Date()}

        componentDidMount(){
          setInterval(() =>{
            this.setState({date: new Date()})
          },1000)

        }

        render(){
          return(
            <div>
              <h1>hello</h1>
              <input type="text" />
              <span>现在是{this.state.date.toTimeString()}</span>
            </div>
          )
        }

      }

      ReactDOM.render(<Time />, document.getElementById("test"));
    </script>
  </body>
</html>
